Steam-piston.



1L0. MONTEAGLE.

STEAM PISTON. APPLICATION FILED MAY I 1913. V

1,094,461, Patented Apr. 28, 1914.

7 4" f 4 W t mmlwl jmlllkl i STEAM-PISTGN.

Longest.

Specification of Letters Patent.

Patented Apr. 2s, ieie.

Application filed May 1, 1913. Serial No. 764,800.

To all whom it may concern:

Be it known that I, Ronnnr C. MONTEAGLE, a citizen of the United States, residing at West Newton, in the county of Middlesex and State of Massachusetts, have invented an Improvement in Steam-Pistons, of which the following is a specification.

it is customary to provide steam engine pistons with annular recesses in which spring metal rings are arranged, said rings being split, so that they constantly tend to expand and thus constantly press their hearing surfaces firmly against the walls of the cylinder. As there must be a sliding fitbe tween the sides of one of the rings of this character and th sides of the annular recess in which it is placed, a certain amount of steam will leak between these surfaces, which are next the end of the piston adjacent thereto, and pass into the space between the inner side of the ring and the bottom of the recess, so that the strain'tends to press the ring outwardly and thus cause it to be forced against the cylinder wall with greater force than that with which it is normally forced by its spring tension. This tends to cause the ring to bear against the wall of the cylinder with toomuch force, thereby causing an undue amount of friction and wear. The effect 01' this outward pressure has been, to an extent,

neutralized by the provision of a groove in the middle of the outer face of the-ring, and the connection of said groove with the inner side thereof by means of one or more holes, so that the steam which collected between the ring and'the bottom of] the groove escaped into this groove and the effective pressure on the inner side of the rin was counteracted to an extent corresponding to the area. of the annular groove An object, of my invention is to provide a form of ring with which the outward pressure, due to the backing up of steam in the annular groove, will be further reduced and with which the escape of steam about the ring through said groove will be more effect ivcly checked;

It is customary to counterbore the ends of steam cylinders, so that the packing-rings at the ends of the piston will pass over the counterbore to a slight extent, to prevent the wearing of a shoulder at the end of the stroke oft-he piston, against which the ,piston would, in time, pound. In centrally grooving the bearing surface of the packin rings, as above described, the width of said surface is considerably reduced and a very accurate adjustment of the limits of move nient of the piston is necessary to prevent the adjacent bearing surface from passing entirely over the counterbore and yet. to cause it to pass thereover to an extent.

A further object of my invention is to provide a construction of packing-ring having the above described characteristics and in which the leeway for adjustment as to the limits of the piston stroke is increased.

I accomplish these objects by the means shown in the accompanying drawing, in which,

Figure 1 is a central cross-section of a steam piston and cylinder made according to my invention. Fig. 2 is a detailed sectional view of the packing-ring. Fig. 3 is an edge View thereof. Fig. 4 is a detailed sectional View of a modification.

According to my invention the cylinder (1 is provided with a piston Z) having an annular groove 0, therein, adjacent each end, and, as the construction at each end is the same, so far as the present invention is concerned, a description of the construction at one end will suflice. One side of the groove 0, is formed by a head plate d, and the surface cl thereof, on said plate, is perpendicular to the surface of the piston, and the opposite side, formed by the body of the piston, is slightly inclined toward the .end of the cylinder, asitextends outwardly. A split packing ringf is arranged in the groove 0, said ring being of spring metal and having overlapping ends and a joint breaker g to provide a practically continuous ring, as shown in Fig. 3, said construction being well known. The side of the ring next the head plate d is erpendicular, and the opposite side isslightly inclined to correspond to the inclination of the side of the groove 0, so that, as the ring f is forced outwardly it will be wedged between the sides of the groove to prevent looseness between said sides, as the contacting surfaces become worn.

According to my invention I arrange the inner surface f of the ring at an acute angle to the side cl thereof, so that, when the steam pressure is applied to the inner surface of the ring, instead of having all the pressure on said surface act outwardly, at right angles to the surface of the cylinder, it will have a component longitudinally of the cylinder against the head plate (Z, so that a oortion of this outward pressure will be ecclive in forcing the ring f more firmly against the plate 03, with the result that, with this arrangement, the ingress of steam to the space between the ring and the bottom of the groove will be, to an extent, further prevented.

A series of apertures f are provided in the ring f, which extend from the'inner to the outer side thereof, and an annular groove f is provided in the outer surface of the ring to which said apertures lead. According to my invention I arrange this annular groove f at one side of the middle of said ring, sothat the bearing-surface f", between said groove and said face is of materially greater width than the surface f at the opposite side of said grooves. With this arrangement I thus provide a relatively wide bearing surface at the steam side of the ring, so that, while the surface which is effective to counterbalance theoutward pressure from the chamber at the bottom of the groove in the cylinder, is not reduced, materially, more leeway for adjustment of the stroke of the piston with relation to the counter-bore a of the cylinder, is provided, so that the surface f may be carried over the counterbore at one edge without having it carried completely thereover.

As shown ,in Fig. 4, I may provideall the against the walls of the cylinder, the angle between the side of said ring next the piston end and the inner side of said ring being less than a right angle, to cause the force of the steam-pressure between the ring and the bottom of the recess to have a component to press the ring against the side of the groove next the piston end, substantially as described. I

2. A steam piston having an annular recess adjacent its end adapted to receive steam pressure, a split spring metal packingring fitted in said recess and adapted to expand against the walls of the cylinder, the

side of the recess next the piston end, and

the corresponding'side of the ring being perpendicular to the outer surface of the ring and the angle between said side of the ring and its bottom being less than a right angle, as and for the purpose set forth.

3. A steam piston having an annular recess, a split, spring-metal packing-ring fitted in said recess and ada ted to expand against the walls of the cylinder, said ring having an annular groove formed in its outer surface and an aperture therethrough leading from the inner side thereof to said groove, whereby the bottom of said groove may act as a balancing surface to outward pressure on the lnner side of said ring, the

port-ion of said balancing surface at the opposite side ofthe middle of the ring from the piston end being materially greater than that at the adjacent side, substantially as described.

In testimony whereof, I have signed my name to this specification, in the presence of two subscribing witnesses.

ROBERT c. MONTEAGLE.

Witnesses L. HARRIMAN, H. B. DAVIS. 

